A new method for stable lead isotope extraction from seawater.

Area of Science:

• Geochemistry
• Environmental Science
• Analytical Chemistry

Background:

• Accurate measurement of stable lead (Pb) isotopes in seawater is vital for understanding marine biogeochemical cycles and tracing pollution sources.
• Existing methods for Pb isotope extraction can be time-consuming, labor-intensive, and prone to contamination, limiting throughput and precision.

Purpose of the Study:

• To establish a novel, semi-automated technique for the efficient and precise extraction of stable lead (Pb) isotopes from seawater.
• To minimize chemical blank and maximize analytical precision for lead isotope ratio measurements using mass spectrometry.

Main Methods:

• Development and application of a semi-automated extraction protocol utilizing Toyopearl AF-Chelate 650M® resin.
• Minimization of chemical reagent volumes to reduce procedural blank levels.
• Analysis of extracted Pb isotopes using High-Resolution Inductively Coupled Plasma Mass Spectrometry (HR ICP-MS) and Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS).

Main Results:

• The developed method achieved good relative external precision (2σ) of 3.5‰ for (206)Pb/(207)Pb using HR ICP-MS.
• MC-ICP-MS analysis yielded a superior relative external precision of 0.6‰, although limited to (206)Pb, (207)Pb, and (208)Pb due to sample concentrations.
• Validation using NIST SRM-981 and GEOTRACES intercalibration samples demonstrated excellent agreement with established values.

Conclusions:

• The new semi-automated technique provides a fast, reliable, and low-blank method for stable lead isotope extraction from seawater.
• This method enhances the precision of lead isotope measurements, supporting advanced research in marine geochemistry and environmental monitoring.
• The validated protocol is suitable for processing large sample volumes required for global oceanographic studies.